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Medical diagnosis through semiotics. Giving meaning to the sign.

Physicians are engaged in incorporating quantitative methods for making clinical decisions into their practices. An acquaintance with semiotics, the doctrine of signs, may complement this project. A sign stands for something. We communicate indirectly through signs, and by interpreting what signs mean we make sense of our world and diagnose and understand our patients. Thus, through association and inference, we transform flowers into love, Othello into jealousy, and staring eyes into thyrotoxicosis. Characteristically in diagnosis, beginning with an unstable inference, we test and otherwise ask questions likely to produce signs that support (or discredit) our hypothesis. In a literary sense, we join with the author to clarify and rewrite the text; creative interpretation is the key. Diagnosis is concluded through narration, by the meaning that is revealed by telling the story of the patient. Diagnosis will succeed only to the extent that we respect the principles and caveats of sign interpretation. The sign is both the key to the unknown and the master impersonator. The sign and its meaning are usually not the same; meaning has to be inferred. Because interpretations are made subjectively, they are circumscribed by the experience and bias of the clinician. Moreover, the contexts in which the sign appears shape the meaning of the sign and may change it altogether.

Clinical Competence↗

[Collection of Arabidopsis thaliana mutants with altered sensitivity to oxidative stress inductors].

Selective systems for screening Arabidopsis thaliana (L.) Heynh. mutants with altered sensitivity to the oxidative stress (OS) inductors norflurazon (NF), acifluorfen (AF), and plumbagin (PB) were developed and a collection of 28 mutants was obtained. Dwarf and necrotic forms predominated among the NF-tolerant mutants, while pigment mutants and those with changed root morphology prevailed among the AF-tolerant and PB-sensitive mutants, respectively. Genetic and biochemical analysis of certain mutants was performed; quantitative and qualitative changes in the content of superoxide dismutase and peroxidase isoforms have been revealed. These data, complemented by the data on the cross-tolerance (sensitivity) of the mutants to paraquat, indicate a correlation between tolerance to the OS inductors and the functions of antioxidant systems.

Arabidopsis↗

[The clinical immunology laboratory in diagnosis and monitoring of systemic lupus erythematosus and connective tissue diseases].

The laboratory and particularly clinical immunology laboratories have an essential role in diagnosing and monitoring systemic lupus erythematosus (SLE), as well as other connective tissue diseases. The role of the clinical immunology laboratory in these diseases is to confirm or exclude diagnosis, to monitor disease activity, and to identify subgroup of patients. To obtain the best results in terms of diagnostic performance and clinical usefulness, the following recommendations should be fulfilled: anti-nuclear antibodies (ANA) determination by indirect immunofluorescence on Hep-2 cells is an effective screening assay in patients with clinical features of SLE. A negative ANA test makes the diagnosis of SLE unlikely. Anti-dsDNA antibodies are highly specific for SLE and are associated with renal involvement. The method of choice for anti-dsDNA is the Farr assay; however, the necessity of using radioactive materials reduces its applicability. As an alternative, immunofluorescence on Crithidia Luciliae can be used in the diagnostic phase due to its high specificity. The detection of antibodies to extractable nuclear antigens (ENA) and to phospholipids (lupus anticoagulant and anti-cardiolipin antibodies) is useful in identifying subgroups of patients at risk for some clinical manifestations. Anti-dsDNA measurement with a quantitative assay (the Farr assay or ELISA) is currently the best method to monitor disease activity along with complement levels. New assays (anti-C1q and anti-nucleosome antibodies) have been recently proposed for the diagnosis (anti-nucleosome) and monitoring of SLE patients (anti-C1q and anti-nucleosome antibodies), with promising results.

Algorithms↗

[Use of microbiologic-serologic studies for Chlamydia and Mycoplasma in differential diagnosis of inflammatory rheumatic diseases].

Chlamydiae are obligate intracellular bacteria that lack ATP-synthesis; mycoplasmas are free-living bacteria without cell walls. Chlamydia trachomatis and mycoplasmas may be associated with reactive rheumatic diseases. Local chlamydial infections are identified by isolating the bacteria in cell cultures or by detecting bacterial antigens in specimens containing epithelial cells. Disseminated chlamydial infection can be detected by specific serum antibodies. Mycoplasma infections of the genitourinary tract are detected by quantitative isolation methods. Diagnosis of Mycoplasma pneumoniae infections requires demonstration of a rise in specific serum antibodies using complement fixation or indirect hemagglutination tests. For the diagnosis of reactive rheumatic diseases, the microbiological and serological findings have to be connected synoptically with other laboratory data and with the clinical symptoms.

Adult↗

[Non allergic skin reactions of drugs (author's transl)].

Non allergic skin reactions are differentiated in the following way: overdose, idiosyncrasy, intolerance and side effects. An intoxication caused by an overdose of a drug may be initiated by an increased resorption through the skin (e. g. salicylic acid or the obsolete boric acid). An overdose of a drug often leads to coma and in many cases, if the patients are lying unattended (e. g. at home). ischemic skin reactions, such as blisters or necrosis occur at pressure areas. Intolerance is an undesirable reaction, produced by a normal therapeutic dose of the drug. Reactions of special interest are those imitating an anaphylactic reaction (type I), such as histamine liberation, complement activation or intolerance to analgetics, dyes or preserving agents. Idiosyncrasy summarizes reactions, which differs both qualitatively and quantitatively from the normal response to therapeutic dose of a drug. Additionaly these reactions are characterized by an underlying biochemical disturbance: drug-induced porphyric crisis in porphyria acuta intermittens, INH induced pellagra or drug-induced lupus erythematosus are discussed in this context in greater detail. Side effects of a drug is a misnomen, but this term cannot be done without. These undesired effects can be differentiated into obligatory effects as seen after cytostatic treatment in the form of alopecia; and possible reactions such as chloasmas after treatment with oral hormonal contraceptives. We assume that some of these side effects would belong to the category of idiosyncrasy or intolerance, if their pathogenesis were known.

Anaphylaxis↗

Use of solid-phase extraction disks for analysis of moderately polar and nonpolar pesticides in high-moisture foods.

This study investigated the use of solid-phase extraction (SPE) disks in analysis of high-moisture (< 2% fat) foods for organophosphorus and organochlorinated pesticides with low (< 25 mg/mL) water solubilities. Five representative foods were each spiked with one of 18 pesticides at 2 levels. Gas chromatography with flame photometric and electrolytic conductivity detection was used to quantitate organophosphates and organochlorinated pesticides, respectively. Essentially complete recoveries (> or = 80%) suggest that use of SPE disks can complement traditional liquid-liquid extraction procedures.

Chromatography, Gas↗

Characterization of cells that suppress the cytotoxic activity of T lymphocytes. I. Quantitative measurement of inhibitor cells.

Target cell lysis by sensitized cytolytic T lymphocytes (CTL) may be conveniently quantitated by 51Cr release. By fitting to the formula, P (% specfic release) = 100 (1-e-Nat) one obtains alpha, the relative frequency of CTL in N lymphoid cells. Using a microassay and murine sarcoma target cells, we observed an unexpected decrease in lysis whenever effectors obtained from a graft-vs-host reaction were tested at high concentrations. This inhibition was not observed with CTL generated by an MLC reaction. Inhibition could not be explained by nonspecific mechanical 'crowding', reutilization of released isotope, suppression of release from dead target cells, or the particular strain combination and target used. By modifying the formula to allow suppression of CTL by a stochastic cell-cell interaction with suppessor cell, we found that P = 100 (1-e-Nate-Ngamma) adequately fitted the data, where Ngamma is proportional to inhibitor content. An 18- to 24-hr incubation at 37 degrees C but not 4 degrees C allowed selective depletion or enrichment of inhibitors; in mixing experiments, both parameters Nalpha t and Ngamma behaved stoichiometrically as independent cellular properties. The inhibitor was resistant to concentrations of anti-T cell (RAMG) serum + complement which killed -TL. A similar inhibitor arose in vivo during an anti-tumour allograft response. The ability to quantitate CTL and inhibitor activities from titration curves provides a technique for studying the identity and mechanism of suppressor cells acting at the effector stage of cell-mediated immunity.

Animals↗

Cold-dependent activation of complement: recognition, assessment, and mechanism.

Cold-dependent activation of complement (CDAC) is a phenomenon characterized by low hemolytic complement activity in chilled serum. Complement component levels are normal when measured immunologically, and there is normal hemolytic activity in EDTA plasma or serum maintained at 37 degrees C. Little attention has been paid to CDAC except in Japan, and current unfamiliarity with it, even by clinical immunologists, can lead to confusion and unnecessary laboratory tests. A 66-year-old patient with a complex medical history is described whose complement tests showed abnormalities characteristic of CDAC. Evidence for classical complement pathway activation in the cold was obtained by CH50 measurements, by hemolytic C4 determinations, by C4a, C3a, and C4d generation, and by quantitating C1s-C1r-(C1 inhibitor)2 complexes. A good correlation was observed among these parameters. Cryoprecipitates were absent. CDAC activity has persisted for over 5 years and is greater at 13 than at 4 degrees C. Activation is ablated by heating at 56 degrees C and restored by the addition of C1 to the heated serum. Adsorption by streptococcal protein G-Sepharose and precipitation by 2.5% polyethylene glycol support the hypothesis that CDAC is caused by aggregated IgG. The CDAC factor(s) also induces complement activation in normal serum but has not interfered with Raji cell or C1q binding tests or with FACS analysis. More limited studies of a second individual experiencing CDAC yielded similar results.

Adult↗

A quantitative assay for cytolysis induced by Newcastle disease virus.

We report here an assay for quantifying virus-induced lysis, in the absence of antibody and complement, produced within 2 hr after adsorption. This technique makes use of 51CrO4 release from cell monolayers pre-incubated overnight with the isotope. The release of 51Cr is specific for virus-induced lysis and is suppressible by 0.001 M-Ca2+. This assay clearly distinguishes between wild-type Chinese hamster ovary (CHO) cells, clone K and fusion-resistant mutant (CHO-15B), which was found to be resistant to virus-induced cytolysis. The stability of the association of isotope with monolayers of this cell type under the labelling conditions described makes this technique applicable to the study of the cytolytic effects of virus infection.

Animals↗

C5a anaphylatoxin as a product of complement activation up-regulates the complement inhibitory factor H in rat Kupffer cells.

The 155-kDa complement regulator factor H (FH) is the predominant soluble regulatory protein of the complement system. It acts as a cofactor for the factor I-mediated conversion of the component C3b to iC3b, competes with factor B for a binding site on C3b and C3(H2O) and promotes the dissociation of the C3bBb complex. The primary site of synthesis is the liver, i.e. FH-specific mRNA and protein were identified in both hepatocytes (HC) and Kupffer cells (KC). Previous studies in rat primary HC and KC had shown that the proinflammatory cytokine IFN-gamma influences the balance between activation and inhibition of the complement system through up-regulation of the inhibitory FH. In this study we show that C5a, as a product of complement activation, stimulates the expression of FH-specific mRNA and protein in KC and thus induces a negative feedback. Quantitative-competitive RT-PCR showed an approximate threefold C5a-induced up-regulation of FH. ELISA analyses revealed a corresponding increase in FH protein in the supernatants of KC. The up-regulation of FH was completely inhibited by the C5a-blocking monoclonal antibody 6-9F. Furthermore, an involvement of LPS and IFN-gamma was excluded, which strongly indicates a direct effect of C5a on the expression of FH in KC.

Animals↗

Transgenic mice overexpressing the complement inhibitor crry as a soluble protein are protected from antibody-induced glomerular injury.

Complement receptor 1-related gene/protein y (Crry) is a potent murine membrane complement regulator that inhibits classical and alternative pathway C3 convertases. In nephrotoxic serum (NTS) nephritis, injected antibodies (Abs) bind to glomeruli, leading to complement activation and subsequent glomerular injury and albuminuria. To study the phenotypic effects of continuous complement pathway blockade, transgenic mice were created that express recombinant soluble (rs) Crry directed by the broadly active and heavy metal-inducible metallothionein-I promoter. One transgenic line expressing high levels of rsCrry was propagated. Serum rsCrry levels were 18.7 +/- 2.7 microg/ml (n = 5) at basal level and increased to 118.1 +/- 20.6 microg/ml 4 d after addition of zinc to the drinking water. By reverse transcription polymerase chain reaction (RT-PCR), transgene messenger (m)RNA was present in liver, kidney, brain, lung, and spleen, but not in heart. By in situ RT-PCR analysis of kidneys, transgene mRNA was widely expressed both in renal glomeruli and tubules. Urinary excretion of rsCrry was 113.4 +/- 22.4 microg/ml with a fractional excretion relative to creatinine of 13.2 +/- 2.7%, consistent with local renal production of rsCrry and secretion into urine. The founder and all transgene positive adult animals have remained healthy with no mortality or apparent phenotypic abnormalities, including infection or immune complex disease. To determine whether rsCrry blocked complement-mediated injury, NTS nephritis was induced by injection of NTS immunoglobulin (Ig)G, followed by an 18-h urine collection to quantitate the excretion of albumin as a measure of glomerular injury. In transgene-negative littermates (n = 15), transgene-positive animals (n = 10), and transgene-positive animals fed zinc (n = 10), albuminuria was 4,393 +/- 948, 1,783 +/- 454, and 1,057 +/- 277 microg/mg creatinine, respectively (P < 0.01 by ANOVA). Glomerular C3 was evident by immunofluorescence staining in 12/15 transgene-negative animals, but in none of the transgene-positive animals fed zinc. Thus, we have produced the first transgenic animals that overexpress a soluble C3 convertase inhibitor. rsCrry expression markedly ameliorates an Ab-induced disease model in vivo. These results support the hypothesis that continuous complement inhibition at the C3 convertase step is feasible and effective in complement-mediated injury states.

Animals↗

Sperm immobilizing antibodies interfere with sperm migration from the uterine cavity through the fallopian tubes.

PROBLEM: It is well known that sperm migration in cervical mucus is impaired by sperm immobilizing antibodies secreted in the mucus. However, it is not clear yet whether sperm migration from the uterine cavity through the fallopian tubes to the peritoneal cavity is impaired by sperm immobilizing antibodies. To test the possible impairment of sperm migration in the tubes, laparoscopic examinations were carried out and the presence of motile sperm in the peritoneal fluid after intra-uterine insemination was investigated. METHOD: Peritoneal sperm recovery tests were performed in 28 infertile women with sperm immobilizing antibodies in their sera, and the results were compared with those in 322 infertile women without the antibodies. Both the sperm immobilizing antibody titers (SI50) and complement activities (C'H50) in peritoneal fluid were compared with those in patients' sera. In some experiments, the supernatant of the peritoneal fluid was used as a source of complement for the sperm immobilization tests instead of guinea pig serum. RESULTS: Among couples with normal semen characteristics by the criteria of WHO, sperm recovery in the peritoneal fluid was observed in only 3 (11.1%) of 27 patients with sperm immobilizing antibodies, compared with 72 (34.0%) of 212 patients without the antibodies (P < 0.025). The antibody titers of the patients with the sperm recovery were very low by the quantitative sperm immobilization test. In most patients, a similar amount of sperm immobilizing antibodies was present in the peritoneal fluid and the sera. Though the complement activities in the peritoneal fluid were less than those in sera, the former were still found to be sufficient to immobilize sperm in vivo. CONCLUSIONS: These results suggest that the complement-dependent sperm immobilizing antibodies could interfere with sperm migration in the female genital tract at the level of the fallopian tubes.

Animals↗